Honda Express Performance questions
There are other cylinders that will fit an Express. Anything for Honda - Camino, PX, PA and some others will work. I have 65cc Metrakit that installed on my NU50 Urban with no modifications, ie: hole plugs, chopping fins, etc. They have a couple of oversize ring kits available too (.010, .020). Make sure you can get oversized bore/ring sizes in case you seize it.